1. Field of the Invention
The present invention is in the field of accumulator devices, and more particularly pertains to an accumulator device intended to be employed in a hydraulic system as a means for dampening pulsations or storing energy.
2. The Prior Art
It is known to employ in a hydraulic system for various purposes, such as pulsation dampening and energy storage, an accumulator device which comprises a pressure vessel having an oil or liquid port adapted to be connected in a hydraulic line. A bladder assembly is disposed within the vessel, access being provided to the interior of the bladder for charging the same with gas under pressure. When the oil pressure exceeds the pressure of the gas charged in the bladder, oil is permitted to enter through the oil port into the interior of the vessel and further compress the gas within the bladder. When the pressure in the hydraulic line falls, the bladder expands and the energy stored in the gas is retransmitted to the hydraulic system.
Numerous means for mounting the bladder within the vessel are in commercial production. In certain instances, the open mouth of the bladder is bonded to an annular ring which, in turn, is welded to the interior walls of the pressure vessel.
In alternative constructions, the retaining ring bonded to the bladder is welded to one half of the pressure vessel and a second weld line completes the formation of the vessel and secures the ring in position.
In still further versions of known accumulators, the open mouth or gas charging opening of the bladder is secured to a stem member, which stem member is, in turn, mounted in a bore formed at one end of the pressure vessel. In devices of the last mentioned type, in order to assure against leak of oil and of gas, complex arrangements of O-rings, clamps and like structures have been required.
A further difficulty inhering in devices heretofore known wherein a mounting stem provides the means for securing the bladder in position, lies in the tendency of the bladder to separate from the stem under operating conditions, with resultant failure of the accumulator.
As examples of stem mounted bladder type accumulators heretofore known, reference is made to U.S. Pat. Nos. 3,230,975 of Jan. 25, 1966; 3,232,318 of Feb. 1, 1966; and 3,920,047 of Nov. 18, 1975.